Artificial teeth and method of assembling same



Dec. 25, 1956 M. BERESIN 2,775,035

ARTIFICIAL TEETH AND METHOD OF ASSEMBLING SAME Filed May 16, 1955 2 Sheets-Sheet 1 mm Mu 4 e2 5 70 {0 50 @2 7178 J i i A I I 66 if i a 5 i h a 22 40 #2 8 INVENTOR. MaP/P/S BEPff/N Amp/w Dec. 25, 1956 M. BERESIN 2,775,035

ARTIFICIAL TEETH AND METHOD OF ASSEMBLING SAME Filed May 16, 1955 2 Sheets-Sheet 2 INVENTOR. MOP/W5 Bf/QES/N ATTO/P/VE) United States Patent ARTIFICIAL TEETH AND METHOD OF ASSEMBLING SAME Morris Beresin, Philadelphia, Pa.

Application May 16, 1955, Serial No. 508,433

42 Claims. (Cl. 328) This invention relates to artificial teeth and the method of assembling same, and more particularly to artificial teeth of the non-anatomical type and the method of assembling same for occlusal balance and mandibular control.

Heretofore non-anatomical teeth have been produced and assembled to form dentures. tures have left much to be desired in the efficiency of their performance, their guidance of mandibular movements, and the naturalness of their appearance.

It is therefore a primary object of this invention to provide new and improved artificial teeth and dentures of the non-anatomical type having increased masticating efliciency.

Another object of the invention is to provide new and improved dentures having artificial non-anatomical teeth arranged to produce occlusal balance and mandibular control.

Still another object of the invention is to provide new and improved artificial teeth and dentures of the nonanatornical type which give the natural appearance of anatomical teeth.

Yet another object of the invention is to provide new and improved dentures in which interlocking, tilting and tipping of the upper and lower plates are eliminated.

A further object of the invention is to provide dentures utilizing artificial teeth of the non-anatomical type producing increased masticating pressures with the application of normal forces for greater efiiciency.

Still a further object of the invention is to provide new and improved dentures utilizing artificial teeth of the nonanatomical type in which the lengths of the crowns of the incisor may be properly proportioned for natural appearance without reducing the masticating efiiciency of the dentures.

Yet a further object of the invention is to provide a new and improved method for assembling artificial teeth of the non-anatomical type for occlusal balance and mandibular control.

Another object of the invention is to provide a new and improved method for assembling artificial teeth of the non-anatomical type in which the respective lengths of the crowns of the upper and lower incisor teeth can be relatively adjusted.

Still another object of the invention is to provide new and improved artificial teeth of the non-anatomical type which may be easily cleaned and maintained in good condition.

Yet another object of the invention is to provide new and improved artificial teeth of the non-anatomical type which are natural in appearance.

A further object of the invention is to provide new and improved artificial teeth of the non-anatomical type having predetermined configurations and forms especially adapted for assembly in artificial dentures without requiring further grinding or finishing operations.

Still a further object of the invention is to provide new and improved artificial teeth of the non-anatomical type These teeth and denwhich may be efliciently manufactured at a minimum cost.

The foregoing is attained as well as other objects by arranging artificial teeth of the non-anatomical type to form upper and lower dentures. The top contact surfaces of the artificial teeth are preformed and positioned to conform with the surface of a respective one of two concentric spheres.

The top contact surfaces of the lower anterior teeth are concave and positioned to conform with the surface of the first sphere, while the top contact surfaces of the lower posterior teeth are also concave and positioned to conform with the surface of the second sphere. The second sphere is concentric with and has a radius less than that of the first sphere. In a similar manner the upper anterior teeth which are convex, conform with the surface of the first sphere, while the upper posterior teeth conform with the surface of the second sphere.

Since the top contact surfaces of the upper and lower anterior teeth conform to the surface of the first sphere, and the top contact surfaces of the upper and lower posterior teeth conform to the surface of the second sphere, one denture may move with respect to the other within the operating range without interfering and locking. The two spherical occlusal surfaces also provide occlusal balance, and act to effectively guide and limit excessive mandibular movement in the protrusive direction because of their different levels.

The radius of the first sphere may be varied to adjust the relative crown lengths of the upper and lower incisor teeth. This adjustment maintains the natural appearance of the dentures without disturbing their occlusal balance.

The cuspid teeth upon their labial surfaces and the bicuspid and molar teeth upon their buccal surfaces are each provided with at least one vertically extending protrusion for increasing their masticating efliciency and the naturalness of their appearance.

Crowns of the posterior teeth are provided with ocolusal portions having conical cusps and band cusps. The cusps have top contact portions conforming to the surface of a sphere of predetermined radius. For example, while the top contact surfaces of the anterior teeth may be on the surface of a sphere having a radius of 4% inches, the top contact surfaces of the posterior teeth may be on the surface of a sphere having a radius of 4 inches. Since the top contact surfaces of the occlusal portions of the posterior teeth have an arcuate or curved cross-section, the actual contacting surface is narrow and may be considered a line contact. The line contact surface serves to exert high masticating pressures with the application of normal forces to the dentures increasing the efliciency of their operation.

The inner inclined surfaces of the cusps meet to form a bottom line. This construction of the occlusal portion of the teeth while not hindering removal of food particles which may otherwise lodge therein, effectively aids the mastica-ting process by gripping the food being acted upon especially during shearing action.

The foregoing and other objects of the invention will become more apparent as the following detailed description of the invention is read in conjunction with the drawings in which:

Figure 1 is a side elevational view illustrating the method of arranging the lower incisor teeth upon a base with their top contact surfaces on the spherical surface of an occlusal guide of predetermined radius.

Figure 2 is a side elevational view illustrating the method of arranging the lower cuspid and posterior teeth with their concave top contact surfaces on the concentric spherical surface of a second occlusal guide of reduced radius,

Figure 3 is a side elevational view illustrating the ar- 3 rangement of the anterior and posterior teeth of the upper denture on a base plate conforming with the contact surfaces of the lower anterior and posterior teeth in the protrusive position,

Figure 4 is a side elevationalview illustrating the teeth of Figure 3 in their centric position,

Figure 5 is a front elevational view of Figure 3,

Figure 6 is an enlarged sectional view taken on the line 6-6015 Figure 5,

Figure 7 is a plan view of the lower denture disclosing in detail the occlusal portion of the crowns of the artificial teeth,

Figure 8 is a plan view of the upper denture which is designed to coact with the lower denture of Figure 7, illustrating the occlusal portion of the crowns of the upper artificial teeth,

Figure 9 is a perspective view of the upper and lower dentures respectively of Figures 7 and 8 in their centric position,

Figure 10 is an enlarged plan view showing in detail the configuration of the occlusal surface of the lower first molar tooth, and

Figure 11 is a sectional view taken on the line 11-11 of Figure 10.

Like numerals represent like parts throughout the several views.

Refer now to Figures 1 to 6 inclusive which illustrate in detail the novel method of assembling and positioning artificial teeth of the non-anatomical type. These teeth have top contact surfaces conforming with the surface of a sphere and are arranged to form complementary upper and lower dentures embodying the invention.

As shown by Figure 1, the lower manibular cast of an edentulous month has its ridge covered by a base plate 22 of tacky or wax material in the usual manner of preparing dentures.

The lower central incisors 24, 25 and the lower lateral incisors 26, 27 are positioned by the base plate 22 on the crest of the ridge of the mandibular cast 20. so that their concave top contact surfaces lie on the spherical surface 28 of guide 39. The surface 28 has a center 32 with a radius 33 of about 41 8 inches. The center and radius of the surface 28 of the spherical guide 34) may, of course, be varied in accordance with design requirement.

As shown in Figure 2, the occlusal guide may be replaced by occlusal guide 34 with a spherical surface 36 which has the same center of generation 32. The generating radius 38 of the spherical surface 36 is less than the radius 53 of the guide 30, and may for example be four inches. The radius of the guide 34 may, however, also be varied in accordance with design considerations.

It is noted that the difference in radius of the concentric spherical surfaces 223, as of the respective guides 30,. 34 is small when compared with either radius. Therefore, a substantially similar result may be achieved by using the same occiusal guide 30 and raising its level to correspond to the reduction of radius of the second spherical surface to which the top contact surfaces of the lower posterior teeth are to be conformed. This is because with such a small variation in the radius of generation, the curvature of the spherical surface 28 of the occlusal guide 30 would vary only slightly from the curvature of the surface 36 of the guide 34.

The lower cuspids 4t), 41 and the lower posterior teeth comprising the bicuspids 42, 43, the second bicuspids-44, 45, the first molars 46 and 47 and the second molars 43 and 49 may now be positioned along the crest of the ridge of the mandibular cast 20 so that their top contact surfaces conform with the spherical surface 36 of the guide 3 5. This is readily accomplished since the top contact surfaces of the teeth are formed to have a concave spherical surface of predetermined curvature which is the curvature of the occlusal guide 34 being used.

it is noted that the cuspids 40, 41 are respectively positioned intermediate the lateral incisors 26, 27 of the anterior teeth and the bicuspids 4'2, 43 of the posterior teeth. Since the incisors are set up against the spherical surface of the occlusal guide 30 and the posterior teeth are positioned to conform with the spherical surface of the occlusal guide 34, the cuspids serve to accommodate the differing spherical contact surfaces of the adjacent teeth. Thus the distal portion 541 of the occlusal surface of each of the cuspids 40, 41 conforms with the surface 36 of the guide 34 while its mesial portion 52 slopes downwardly toward the contact surface of its adjacent incisor 26, 2'7 and forms an apex 54.

The Figure 3 illustrates the manner in which the upper teeth are positioned to correspond with the lower teeth. The upper teeth are in a similar manner set up upon the crest of the ridge of the maxillary cast utilizing a base plate as of tacky or wax composition material.

The upper central incisors 64, and the lateral incisors 66, 67 are provided with'convex contact surfaces conforming with the contact surfaces of the lower incisors.

After the upper incisors have been positioned, the upper cuspids 70, 71 and the upper posterior teeth, namely the first bicuspids 72, 73, the second bicuspids 74, 75, the first molars 76, 77 and the second molars 73, 79 are positioned on the crest of the ridge of the maxillary cast 60. The top contact surfaces of the upper posterior teeth are convex and conform with the spherical occlusal surface of the lower posterior teeth. The contact surfaces of the upper cuspid teeth, like the lower cuspid teeth, are designed for accommodating the differing spherical top contact surfaces of adjacent teeth and for harmoniously coacting with the lower opposing teeth.

Theadvantages of having the top contact surfaces of the dentures conform with concentric spheres are manifold. The natural masticating action of the jaws are arcuate and three dimensional. The spherical occlusal surfaces of the dentures allow the three dimensional arcuate action of the mandible while providing occlusal balance. The occlusal balance inherent in the arrangement of the arti ficial teeth will be obvious from Figures 3 and 4 which illustrate thecon'tact maintained between the upper and lower contact surfaces of the dentures when they move across each other between their protrusive and centric positions. The movement on a spherical occlusal surface also prevents interference between the upper and lower teeth which as in the case of anatomical artificial teeth would cause shifting, tilting, and teetering of the dentures.

It is also very important to note that since the anterior and posterior teeth are on different levels conforming to concentric spheres of different radii, in addition to balanced occlusion, a desirable degree of control and guidance of the movement of the mandible is achieved. For example, when the artificial dentures are in the centric position, occlusal balance is achieved by the contact of the upper andlower posterior teeth.

When the mandible moves the lower denture in the anterior direction to the protrusive position (see Figure 3) occlusal balance is maintained since all of the contacting surfaces of the upper and lower dentures are engaged.

Movement of the mandibleto further extend the lower denture in the protrusive direction is restrained by the higher level of the occlusal surface of the lower posterior teeth which is not in alignment with lower level of occlusal surface ofthe upper anterior teeth. Because of this the lower denture is restricted in its protrusive movement during normal coaction of the upper and lower dentures.

Means of achieving rnandibular'control and guidance is important especially in connection with non-anatomical teeth having spherical occlusal surfaces, since otherwise the mandible has a tendency'to make'excessive excursions Which may result in-deformation andmisalignment of the an l -J,

The dashed line at 36 of Figure 5 illustrates the line of intersection with the upper anterior teeth of the extend ed spherical surface 36 of the guide 34. It is thus evident that if the top contact surfaces of all of the teeth were made to conform with the surface 36 of the guide 34, not only would mandibular control beyond the protrusive position be lost, but the respective lengths of the crowns of the upper and lower incisor teeth would be disproportionate. By conforming the anterior teeth with the concentric spherical surface 28 of greater radius, not only is mandibular control achieved but the lengths of the crowns of the incisor teeth may be properly proportioned to have a natural and asthetic appearance.

By preforming the anterior teeth to have top contact surfaces conforming to one of two concentric spheres, the advantages of non-anatomical posterior teeth utilizing a spherical surface of occlusion are extended to the anterior teeth. The Figure 6 shows in detail the relationship of the lower and upper central incisor teeth 25, 65 in the protrusive position, illustrating the cutting and shearing action of their edges and the balanced occlusion achieved.

Refer now to the Figures 7 to 11 inclusive for a description in greater detail of the occlusal portions of the crowns of the artificial teeth embodying the invention.

The Figure 7 discloses a lower denture 80 made in accordance with the invention comprising a denture base 82 which may be made of a plastic material for retaining the upper anterior and posterior teeth in their proper relationships. Figure 8 likewise illustrates the upper denture 84 comprising the base 86 which retains the upper anterior and posterior artificial teeth. The upper and lower dentures 80, 34 form a coordinated set, and are produced in the usual manner, after the teeth have been set up in the tacky wax material over the respective ridges of the mandibular and maxillary casts 20, 60 in accordance with the method illustrated by the Figures 1 to 6 inclusive.

Keeping in mind that the top contact surfaces of the lower teeth are concave, while the top contact surfaces of the upper teeth are convex, the description of the occlusal surfaces of the lower anterior and posterior teeth will also apply to the occlusal surfaces of the respective anterior and posterior teeth of the upper denture unless otherwise specified.

The lower central and lateral incisor teeth 24, 25, 26, and 27 each have an occlusal portion comprising 'a band cusp with a concave top contact surface conforming to the surface of a sphere.

The lower cuspid teeth 40, 41 are each provided with an occlusal surface having a mesial inclined plane 52 and a distal inclined plane 50 as previously explained in connection with Figure 2. The cuspids 40, 41 are also each provided with an outwardly inclined mesio-labial surface 90 and a disto-labial surface 92 meeting along a vertically extending line 94 forming a labial protrusion of substantial triangular cross-section (see Figures 7 and 9). The protrusions of the cuspid teeth increase the effective occlusal surfaces, thereby enlarging their efficiency, while at the same time the inclined planes give the appearance of naturalness to the teeth.

The lower first bicuspid teeth 42, 43 each have an occlusal portion with a conical central lingual cusp 96 and a conical central buccal cusp 98.

Each of the teeth 42, 43 also has a marginal band cusp 100 which connects the central cusps 96, 98 and provides a mesial spillway 102. Since the occlusal portions of the teeth 42, 43 are arcuate in cross-section the top contact surfaces of the band cusps 100 and the conical cusps 96, 94 which are on the surface of a sphere are so narrow that they may be considered line contacts. The inner inclined surfaces of the cusps also meet to form a bottom line which will be explained in greater detail in connection with the Figure 11.

The lower second bicuspid teeth 44, 45 each have a conical central mesio-lingua'l cusp 104 and a conical central disto-lingual cusp 106 separated by a lingual spill way 108. A conical central. buccal cusp 110 is positioned mesio-distally intermediate the lingual cusps 104, 106. A marginal band cusp 112 of configuration has its ends effectively connected with the lingual cusps 104, 106 with its center portion connecting the buccal cusp 119. The top contact surfaces of the band and central cusps are on the surface of a sphere, and have arcuate cross-sections forming substantially line contacts. The cusps of the bicuspids 44, 45 also have inner inclined surfaces mceting'to form a bottom line.

The lower first molars 46, 47 and the second molars 48, 49 each have a conical central mesi-o-lingual cusp 114 and a conical central disto-lingual cusp 116 separated by a lingual spillway 118 as clearly illustrated by the enlarged view of the first molar 46 in Figure 10. The lower molars are also each provided with a conical central mesio-buccal cusp 120 and a conical central buccal cusp 122 separated by a buccal spillway 124 and groove 126 (see Figure 9). A conical central distobuccal cusp 126 is separated from the buccal cusp 122 by a distal buccal spillway 128 and groove 130. The buccal cusps 120, 122 and 126 are staggered in the mesiodistal direction from the lingual cusps 114 and 116.

A mesial marginal band cusp 132 of G-configuration has its ends respectively connected with the mesio-lingual and mesial-buccal cusps 114, 120 and is provided with a rncsia-l spillway 134. A distal marginal band cusp 136 of G-configuration has its ends connected with the disto-lingual and disto-buccal cusps 116, 126. The top contact surfaces of the band and conical cusps are on the surface of a sphere and are arcuate in cross-section so that the contact area may be considered a line as illustrated by the dashes at 140, the top contact point of the cusp 122 being shown at 142. The inner inclined surfaces 144 of the cusps meet to form a bottom line 146 (see Figure 11).

The upper first molars 77, 76 and second molars 78, 79, are in many respects similar to the lower molars, having a conical central mesio-lingual cusp 148 and a conical central disto-lingual cusp 150 separated by a lingual spillway 152. A conical central mesio-buccal cusp 154 and a conical central disto-buccal cusp 156 are separated by a buccal spillway 158 and groove 160 (see Figures 8 and 9). The buccal cusps 154, 156 are staggered in the mesio-distal direction from the lingual cusps 148, 150.

A mesial marginal band cusp 162 of C-configuration has its ends connected with the central m'esio-lingual and mesio-buccal cusps 148 and 154 and is provided with a mesial spillway 164. A distal marginal band cusp 166 also of C-configuration has its ends respectively connected with the central dis-to-lingual and disto-buccal cusps 150 and 156 and is provided with a distal spillway 168. The top contact surfaces of the band and conical cusps are also convex on the surface of a sphere and arcuate in cross-section substantially providing line contacts. The inner inclined surfaces of these cusps likewise meet to form a bottom line as illustrated in the Figure 11.

The buccal surfaces of the posterior teeth may each also be provided with outwardly inclined buccal protrusions 170 of substantially triangular cross section. Such buccal protrusions increase the effective occlusal portion of the tooth while its inclines give the appearance of naturalness to the non-anatomical teeth.

By the described use and arrangement of central conical and marginal band cusps in non-anatomical teeth, occlusal surfaces of increased masticating efficiency are produced. The form and positioning of the cusps pro vide an arrangement of top contacting surfaces and inner inclined surfaces which allow the application of high pressures in the cutting, shearing, and mashing of food. While the marginal =C shaped band cusps encompass the food, the inclined planes ensure its retention and the centrally located cusps interact to increase rnasticating efiectiveness.

Since the cusps are arcuate in cross-section as plainly shown in Figure 11, the top contact areas of the cusps are in effect narrow bands or lines which coact with the narrow line top contact surfaces of the opposing teeth. By this action the applied masticating forces are con centrated at specific regions increasing the pressures which are effected during mastication. As the upper and lower teeth move over each other along the spherical surface of occlusion, opposing contact areas are continually changing, thereby increasing the effectiveness and distribution of masticating force along the occlusal plane.

Since the inner inclined surfaces of the cusps of the posterior teeth meet to form a bottom line, flat bottom surfaces which are not fully effective in mastication are eliminated. This arrangement also provides an occlusal surface which does not tend to retain particules in it and allows easy cleaning of the occlusal surfaces. This structure also enables the teeth to be efficiently manufactured.

Adequate spillways are provided which enhance the masticating efficiency and operation of the non-anatomical teeth. It is also important to note that the teeth embodying the invention, although non-anatomical in structure, match the natural appearance of anatomical teeth. This is significant in that persons wearing dentures are not only interested in the efficiency and comfort afforded by them but are concerned that the dentures give the appearance of natural teeth.

It will be obvious to those skilled in the art that the invention may find wide application with appropriate modification to meet the individual design circumstances, without substantial departure from the essence of the invention.

What is claimed is:

1. An artificial posterior tooth comprising a crown with an occlusal portion having a conical cusp, and a band cusp connecting with said conical cusp, the top contact surfaces of said cusps being on the surface of a sphere.

2. An artificial posterior tooth comprising a crown with an occlusal portion having a conical cusp, and a band cusp connecting with said conical cusp, the top contact surfaces of said band and conical cusps being on the surface of a sphere and being arcuate in cross section to provide substantially line contacts.

3. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of conical cusps, and a marginal band cusp connecting with said conical cusps, the top contact surfaces of said band and conical cusps being on the surface of a sphere.

4. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central conical cusps, and a marginal band cusp connecting with said conical cusps, the -top contact surfaces of said band and conical cusps being on the surface of a sphere.

5. Au artificial posterior tooth comprising a crown with tan occlusal portion having a plurality of central conical cusps, and a pair of marginal band cusps each connecting with respective central conical cusps, the top contact surfaces of said band and conical cusps being on the surface of a sphere.

6. An artificial posterior tooth comprising .a crown with an occlusal portion having a pair of central conical cusps separated by a spillway, and an 'arcuate marginal band cusp connecting wit-h said conical cusps, the top contact surfaces of said band and conical cusps being on the surface .of .a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

7. An artificial posterior tooth comprising a crown with an occlusal portion having a central lingual cusp and a central buccal cusp, and a marginal band cusp connecting with said conical cusps, the top contact surfaces of said band and conical cusp-s being on a surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

8. An artificial first bicuspid tooth comprisinga crown with an occlusal portion having a conical central lingual cusp and a conical central buccal cusp, and a marginal band cusp connecting with said central cusps and being provided with a mesial spillway, the top contact surfaces of said band and conical cusps being on the surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

9. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central lingual cusps, and .a marginal band cusp connecting with said central cusps, the top contact surfaces of said band and central cusps being on the surface of a sphere, the inner inclined surfaces of said cusps meeting to form .a bottom line.

10. An artificial second bicuspid tooth comprising a crown with an occlusal portion having a conical central mesio-lingual cusp and a conical central disto-lingual cusp separated 'by a lingual spillway, a conical central buccal cusp mesio-distally intermediate said lingual cusps, and a marginal band cusp of C-configuration with its ends respectively connecting with said lingual cusps and its center portion connecting with said buccal cusp, the top contact surfaces of said band and central cusps being on the surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

11. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central lingual cusps, a pair of central buccal cusps, a mesial marginal band cusp connecting with one of said lingual cusp and one of said buccal cusps, and a distal marginal band cusp connecting with the other of said lingual cusps and the other :of said buccal cusps, the top contact surfaces of said band and central cusps being on the surface of a sphere, the inner inclined surface of said cusps meeting to form a bottom line.

12. An artificial molar tooth comprising a crown with an occlusal portion having a conical central mesio-lingual cusp and a conical central disto-lingual cusp separated by a lingual .spillway, a conical central mesio-buccal cusp and a conical central distoabuccal cusp separated by a 'buccal spillw ay and groove and staggered in the Inesiodistal direction from said lingual cusps, a mesial marginal band cusp of C-configuration having its ends respectively connecting with the central mesio-lingual and mesiobuccal cusps and being provided with a mesial spillway, and a distal marginal band cusp of C-configuration having its ends respectively connecting with the central disto-lingual and disto-buccal cusps and being provided with a distal spillway, the "top contact surfaces of said band and conical cusps being on the surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

13. An artificial posterior tooth comprising a crown With an occlusal portion having a pair of lingual cusps, three buccal cusps, a mesial marginal band cusp connecting with one of said lingual cusps and one of said buccal cusps, and a distal marginal band cusp connecting with the other of said lingual cusps and another of said buccal cusps, the top contact surfaces of said band and lingual and b-uccal cusps being on the surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

14. 'An artificial molar tooth comprising a crown with an occlusal portion having a conical central mesio-lingual cusp, a conical central disto-lingual cusp separated from said mesio-lingual cusp by a lingual spil'lway, a conical central mesioabuccal cusp, a conical central buccal cusp separated from said rnesio buccal cusp by a buccal spillway and groove, a conical central disto-buccal cusp separated from said bucca'l cusp by a disto-buccal spillway and groove, said buccal cusps being staggered in the mesio-distal direction from said lingual cusps, a mesial marginal band cusp of G-config-uration having its ends respectively connecting with said mesic-lingual and mesiobuccal cusps and being provided with a mesial spillway, and a distal marginal band cusp of C-configuration having its ends respectfully connecting with the disto-lingual and disto buccal cusps, the top contact surfaces of said band and conical cusps being on :the surface of a sphere, the inner inclined surfaces of said cusps meeting to form a bottom line.

15. An artificial posterior tooth comprising a crown with an occlusal portion having a conical cusp, and a band cusp connecting with said conical cusp, said conicall and band cusps each being provided with a top contact surface.

16. An artificial posterior tooth comprising a crown with an occlusal portion having a conical cusp and a band cusp connecting with said conical cusp, said conical and band cusps each having a top contact surface and being arc-uate in cross-section to provide substantially line contacts.

17. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central conical cusps, and a marginal band cusp connecting with said conical cusps, said conical and band cusps each being provided with a top contact surface.

18. An artificial posterior tooth comprising a crown with an occlusal portion having a plurality of central conical cusps, and a pair of marginal b and cusps each connecting with respective central conical cusps, said conical and band cusps each being provided with a top contact surface.

19. An artificial posterior tooth comprising a crown with an occlusal portion having a central lingual cusp and a central buccal cusp, and a marginal band cusp connecting with said conical cusp-s, said central and band cusps each being provided with a top contact surface and inner inclined surfaces meeting to form a bottom line.

20. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central lingual cusps, and a marginal band cusp connecting with said central cusps, said central and marginal cusps each being provided with a top contact surface and inner inclined surfaces meeting to form a bottom line.

21. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of central lingual cusps, a pair of central buccal cusps, a mesial marginal band cusp connecting with one of said lingual cusps and one of said buccal cusps, and a distal marginal band cusp connecting with the other of said lingual cusps and the other of said buccal cusps, said band and central cusps each being provided with a top contact surface and inner inclined surfaces meeting to form a bottom line.

22. An artificial molar toot-h comprising a crown with an occlusal portion having a conical central mesio-lingual cusp and a conical central disto-lingual cusp separated by a lingual spillway, a conical central mesio-buccal cusp and a conical central disto-buccal cusp separated by a buccal spillway and groove and staggered in the mesio-distal direction from said lingual cusps, a mesial marginal band cusp of C-configuration having its ends respectfully connecting with the central mesio-lingual and mesio-buccal cusps and being provided with a mesial spillway, and a distal marginal band cusp of C-configuratio'n having its ends respectively connecting with the central disto-lingual and disto-buccal cusps and being provided with a distal spillway, said band and conical cusps each being provided with a top contact surface and inner inclined surfaces meeting to form a bottom line.

23. An artificial posterior tooth comprising a crown with an occlusal portion having a pair of lingual cusps, three buccal cusps, a mesial marginal band cusp connecting with one of said lingual cusps and one of said buccal cusps, and a distal marginal band cusp connecting with the other of said lingual cusps and another of said buccal cusps, said band and lingual and buccal cusps each being provided with a top contact surface and inner inclined surface meeting to form a bottom line.

24. An artificial molar tooth comprising a crown with an occlusal portion having a conical central mesio-lingual cusp, a conical central disto-lingual cusp separated from 10 said mesio-lingual cusp by a lingual spillway, a conical central mesio-buccal cusp, a conical central buccal cusp separated from said mesio-ltuccal cusp by a buccal spillway and groove, a conical central disto-buccal cusp separated from said buccal cusp by a disto-buccal spillway and groove, said buccal cusps being staggered in the mesio-distal direction from said lingual cusps, a mesial marginal band cusp of (t-configuration having its ends respectively connecting with said mesio-lingual and mesiobuccal cusps and being provided with a mesial spillway, and a distal marginal band cusp of C-configuration having its ends respectively connecting with the disto-lingual and disto-buccal cusps, said conical and band cusps each being provided with a top contact surface and inner inclined surfaces meeting to form a bottom line.

25. An artificial denture including a first group of related teeth and a second group of related teeth each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of the first group of teeth being on the surface of a first sphere, the top contact surfaces of the second group of teeth being on the surface of a second sphere.

26. An artificial denture including a first group of related teeth and a second group of related teeth each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of the first group of teeth being on the surface of a first sphere of predetermined radius, the top contact surfaces of the second group of teeth being on the surface of a second sphere of predetermined radius less than the radius of said first sphere.

27. An artificial denture including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of said anterior teeth being on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth being on the surface of a second sphere of predetermined radius less than the radius of said first sphere.

28. An artificial denture including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact surface, the top cont-act surfaces of said anterior teeth being on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth being on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere.

29. An artificial lower denture including anterior and posterior teeth each comprising a crown with an occlusal portion having a concave top contact surface, the top contact surfaces of said anterior teeth being on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth being on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere.

30. An artificial lower denture including incisors, cuspids, bicuspids, and molars each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of said incisors being concave and on the surface of a first sphere of predetermined radius, the top contact surfaces of said bicuspids and molars being concave and on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere, the top contact surfaces of said cuspids accommodating the differing spherical top contact surfaces of adjacent incisors and bicuspids.

31. An artificial upper denture including anterior and posterior teeth each comprising a crown with an occlusal portion having a convex top contact surface, the top contact surfaces of said anterior teeth being on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth being on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere.

32. Artificial lower and upper dentures including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of said anterior teeth of said dentures in protrusive position being on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth of said dentures in protrusive position being on the surface of a second sphere of predetermined radius less than the radius of said first sphere.

33. Artificial lower and upper dentures including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of said anterior teeth of said lower and upper dentures in protrusive position being respectively concave and convex on the surface of first sphere of predetermined radius, the top contact surfaces of said posterior teeth of said lower and upper dentures in protrusive position being respectively concave and convex on the surface of a second sphere concentric with and having predetermined radius less than the radius of said first sphere, the radius of said first sphere being fixed to determine the relative crown lengths of the respective lower and upper incisors.

34. Artificial lower and upper dentures including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact sur face, the top contact surfaces of said anterior teeth of said lower and upper dentures in protrusive position being respectively concave and convex on the surface of a first sphere of predetermined radius, the top contact surfaces of said posterior teeth of said lower and upper dentures in the protrusive position being respectively concave and convex on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere, the radius of said first sphere being fixed to determine the relative crown lengths of the respective lower and upper incisors, the contact surfaces of said lower denture engaging the contact surfaces of said upper denture in the protrusive position, the contact surfaces of the posterior teeth of said lower and upper dentures remaining in engagement in the centric position.

35. Artificial lower and upper dentures including incisors, cuspids, bicuspids, and molars each comprising a crown with an occlusal portion having a top contact surface, the top contact surfaces of the incisors of said lower and upper dentures in the protrusive position being respectively concave and convex on the surface of a first sphere of radius predetermined to adjust the relative crown lengths of the respective lower and upper incisors, the top contact surfaces of the bicuspids and molars of said lower and upper dentures in the protrusive position being respectively concave and convex on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere, the top contact surfaces of the cuspids of said lower and upper dentures respectively accommodating the differing spherical top contact surfaces of adjacent incisors and bicusiids, the contact surfaces of said lower denture engaging the contact surfaces of said upper denture in the protrusive position, the contacting surfaces of the bicuspids and molars of said respective lower and upper dentures substantially remaining in engagement in the centric position.

36. in an artificial denture including anterior teeth with top contact surfaces on the surface of a first sphere and posterior teeth with top contact surfaces on the surface of a second sphere of reduced radius, an anterior tooth for positioning between anterior and posterior teeth having a top contact surface for accommodating the differing spherical top contact surfaces of adjacent teeth.

37. A method of making artificial dentures which comprises positioning the anterior teeth so that their top 12 contact surfaces conform to the surface of a first sphere of predetermined radius, and positioning the posterior teeth so that their top contact surfaces conform to the surface of a second sphere of predetermined radius less than the radius of said first sphere.

38. A method of making lower artificial dentures which comprises positioning the anterior teeth so that their top contact surfaces conform to the surface of a first sphere of predetermined radius, and positioning the posterior teeth so that their top contact surfaces conform to the surface of a second sphere concentric with and having a radius less than the radius of said first sphere.

39. A method of making lower and upper artificial dentures which comprises positioning the anterior teeth of the lower denture so that their concave top contact surfaces conform to the surface of a first sphere of predetermined radius, positioning the posterior teeth of the lower denture so that their concave top contact surfaces conform to the surface of a second sphere concentric with and having a radius less than the radius of said first sphere, and positioning the anterior and posterior teeth of the upper denture in the protrusive position so that their top contact surfaces conform with the top contact surfaces of the teeth of the lower denture.

40. A method of making lower and upper artificial dentures which comprises positioning the incisors of the lower denture so that their top contact surfaces conform to the surface of a first sphere of radius predetermined to adjust the relative crown lengths of the respective incisors of the lower and upper dentures, positioning the cuspids, bicuspids and molars of the lower denture so that their top contact surfaces conform to the surface of a second sphere concentric with and having a radius less than the radius of said first sphere, adjusting the position of the cuspids of the lower denture so that their top contact surfaces respectively accommodate the differing spherical top contact surfaces of adjacent incisors and biscuspids, and positioning the teeth of the upper denture so that their top contact surfaces conform with and engage the top contact surfaces of the teeth of the lower denture in the protrusive position and the Contact surfaces of the anterior teeth of upper denture maintain engagement with the contact surfaces of the teeth of said lower denture in the centric position.

41. Artificial lower and upper dentures including anterior and posterior teeth each comprising a crown with an occlusal portion having a top contact surface and certain ones of them being provided with a bucco-labial surface with a vertically extending protrusion of substantially triangular cross-section, the top contact surfaces of said anterior teeth of said dentures in the protrusive position being on the surface of a first sphere of radius fixed to adjust the relative crown lengths of the lower and upper incisors, the top contact surfaces of said posterior teeth of said dentures in the protrusive position being on the surface of a second sphere concentric with and having a predetermined radius less than the radius of said first sphere.

42. Artificial lower and upper dentures including incisors, cuspids, bicuspids and molars each comprising a crown with a bucco-labial surface and an occlusal por tion having a contact surface, the cuspids and bicuspids each having outwardly inclined bucco-labial surfaces meeting along a vertically extending central line forming a protrusion of substantially triangular cross-section, the top contact surfaces of the incisors of said lower and upper dentures in the protrusive portion being respectively concave and convex on the surface of a first sphere of radius predetermined to adjust the relative crown lengths of the lower and upper incisors, the top contact surfaces of the bicuspids and molars of said lower and upper dentures in the protrusive position being respectively concave and convex on the surface of a second sphere concentric with and having a pretermined radius less than the radius of said first sphere, the top contact sur 13 14 faces of the cuspids of said lower and upper dentures conical central cusps and a band cusp connecting with a respectively accommodating the differing spherical top pair of said conical cusps, said cusps having inner incontact surfaces of adjacent incisors and bicuspids, the clined surfaces meeting to form a bottom line. contact surfaces of said lower denture engaging the contacting surfaces of said upper denture in the protrusive 5 References Cited in the file of this Patent position, the contact surfaces of the bicuspids and molars UNITED S A PATENTS of saidrespective lower and upper dentures substantially 2 417 965 Beresin Mar 25 1947 remaining in engagement in the centric posltion, the top 2,643,455 Budish June 30 1953 contact surfaces of the occlusal portions of each of the bicuspids and molars being formed by a plurality of 10 

